BIOCHEM 1.2-Introduction to Biomolecules.pdf

INTRODUCTION TO BIOMOLECULES LEARNING OBJECTIVES – Enumerate and differentiate the four biomolecules – Describe biochemical methods used in the study of biochemistry BIOMOLECULES AMINO A CIDS simplest compounds contain an amino group and a carboxyl group have a basic stru...

INTRODUCTION TO BIOMOLECULES LEARNING OBJECTIVES – Enumerate and differentiate the four biomolecules – Describe biochemical methods used in the study of biochemistry BIOMOLECULES AMINO A CIDS simplest compounds contain an amino group and a carboxyl group have a basic structure where a central carbon atom is bonded to a carboxyl group, an amino group, a hydrogen, and a variable group, called the R group difference between the R groups that makes each amino acid unique BIOMOLECULES C ARBOHYDRATES compounds made up of carbon, hydrogen, and oxygen - general formula of (CH2O)n, where n is at least 3 simplest forms are called monosaccharides, or sugars - most common monosaccharide is glucose, which has the formula C6H12O6 simple sugars often make up much larger polymers and are used for energy storage and structural components. BIOMOLECULES N UCLEOTIDES are the basic unit of the hereditary materials DNA and RNA also form the molecular currency of the cell, adenosine triphosphate (ATP) composed of a five-carbon sugar, a nitrogen- containing ring, and one or more phosphate groups BIOMOLECULES LIPIDS most diverse and cannot be shown with a simple structure common to all lipids all have the common trait that they are poorly soluble in water because most of their structure is composed of long chains of hydrocarbons composed of a five-carbon sugar, a nitrogen- containing ring, and one or more phosphate groups  C AN A CHEMIST MAKE THE MOLECULES OF LIFE IN A LABORATORY ? There was a widely held belief in “vital forces,” forces presumably unique to living things. This belief included the idea that the compounds found in living organisms could not be produced in the laboratory. German chemist Friedrich Wöhler performed the critical experiment that disproved this belief in 1828. Wöhler synthesized urea, a well-known waste product of animal metabolism, from ammonium cyanate, a compound obtained from mineral (i.e., nonliving) sources. It has subsequently been shown that any compound that occurs in a living organism can be synthesized in the laboratory, although in many cases the synthesis represents a considerable challenge to even the most skilled organic chemist. The reactions of biomolecules can be described by the methods of organic chemistry, which requires the classification of compounds according to their functional groups.  C AN A CHEMIST MAKE THE MOLECULES OF LIFE IN A LABORATORY ? Friedrich Wöhler - synthesized urea during his experiments, a well- known waste product of animal metabolism, from ammonium cyanate, a compound obtained from mineral (i.e., nonliving) sources. It has been shown that any compound that occurs in a living organism can be synthesized in the laboratory The reactions of biomolecules can be described by the methods of organic chemistry, which requires the classification of compounds according to their functional groups. F UNCTIONAL G ROUPS IMPORTANT IN BIOCHEMISTRY Contain oxygen and nitrogen – among the most electronegative elements As a result, many of these functional groups are polar, and their polar nature plays a crucial role in their reactivity. Esters and anhydrides of phosphoric acid are of vital importance in biochemistry. ATP, a molecule that is the energy currency of the cell, contains both ester and anhydride linkages involving phosphoric acid. F UNCTIONAL G ROUPS IMPORTANT IN BIOCHEMISTRY F UNCTIONAL G ROUPS IMPORTANT IN BIOCHEMISTRY  HOW WERE BIOMOLECULES LIKELY TO HAVE FORMED ON THE EARLY EARTH? Experiments where simple compounds present in the early atmosphere are exposed to conditions that were supposedly existent on the early Earth were performed. These simple compounds react abiotically or in the absence of life, to give rise to biologically important compounds such as the components of proteins and nucleic acids. Miller–Urey experiment A closed system that contains H2, CH4, and NH3, in addition to H2O is exposed to electrical discharge simulating lightning Produced simple organic molecules, such as formaldehyde (HCHO) and hydrogen cyanide (HCn), and amino acids, the building blocks of proteins  HOW WERE BIOMOLECULES LIKELY TO HAVE FORMED ON THE EARLY EARTH? Recent experiments have shown it is possible to synthesize nucleotides from simple molecules by a pathway that includes a precursor that is neither a sugar nor a nucleobase, but a fragment consisting of a sugar and a part of a base. 2-aminooxazole, is highly volatile and can vaporize and condense so as to give rise to pockets of pure material in reasonably large amounts The products include nucleotides that are not part of present- day RNA, but intense ultraviolet light, which was present on the early Earth, destroyed those nucleotides, leaving those found in RNA today.  HOW WERE BIOMOLECULES LIKELY TO HAVE FORMED ON THE EARLY EARTH? The possibility to synthesize nucleotides from simple molecules have been shown Involves a precursor that is neither a sugar nor a nucleobase Fragments consisting of a part of a sugar and a part of a base  HOW WERE BIOMOLECULES LIKELY TO HAVE FORMED ON THE EARLY EARTH? Cells today include very large molecules, such as proteins, nucleic acids, and polysaccharides. These molecules are built from monomers, which can be linked to produce macromolecules called polymers Versatility of carbon is important Tetravalent, able to form bonds with itself and with many other elements giving rise to different kinds of monomers, such as amino acids, nucleotides, and monosaccharides (sugar monomers) Sequence of amino acids determines the properties of the protein formed Genetic code lies in the sequence of monomeric nucleotides that polymerize to form nucleic acids  HOW WERE BIOMOLECULES LIKELY TO HAVE FORMED ON THE EARLY EARTH? END